Understanding the microstructure of particle dispersion in confined copolymer nanocomposites

The microstructures of diblock copolymer/particle composites confined in slitpores have been investigated using a density functional theory approach. It has been shown that, under the condition of confinement, particles display different distributions near the solid surfaces, in the microdomains of two blocks, and at the microphase interfaces. The final dispersion depends on the balance between the enthalpic contribution arising from the particle-segment attraction as well as the entropy-driven depletion attraction induced by the polymer conformation and the confinement environment. For the systems in which particles weakly attract one block but repel another block, particle dispersion can be enhanced by the increasing confinement effect, and the enhancement becomes more obvious as the size asymmetries of particles and two blocks increase. If the attraction increases, however, particle dispersion declines as the confinement effect increases.